OneLook

What OneLook does

OneLook is an English-language reference and word-discovery platform founded in August 1996 and operated by Datamuse, a private US company. The core product is a dictionary search engine that aggregates more than 19 million words drawn from over 1,000 online dictionaries, paired with a thesaurus and reverse dictionary covering over 2 million words and expressions, plus a subject index of 1.5 million words organized into concept clusters. Underlying technology is the Datamuse API, which applies statistical analysis of a large corpus of books written over the past century to generate word associations, synonyms, rhymes, and meaning-based matches. A proprietary pattern syntax (?, *, #, @, -, +, //, comma) supports wildcard, unscramble, and meaning-combined searches that are not widely available elsewhere.

The product surface extends well beyond dictionary lookup. OneLook operates a suite of original word games (Cadgy, Threepeat, Compound Your Joy, Pandergram, Twisteroo, Banish Your Fears), specialty features including a color thesaurus drawing on 2,000+ color names, a history/etymology tab backed by Google Books popularity data, and a quotations search engine called Spruce. Distribution is multi-surface: the main web property, a browser bookmarklet, a free Google Docs Add-On published on the Google Workspace Marketplace, a paid iOS app, and the developer-facing Datamuse API (which is also integrated into RhymeZone, itself used by Merriam-Webster).

OneLook's business model is primarily advertising on the free web service, supplemented by a low-fee iOS subscription with a two-week free trial and developer API access. The company runs a product-led growth motion with no sales team, depending on organic search, word-of-mouth among writers and puzzle communities, and a bi-weekly Wordplay newsletter. The company is privately held with no disclosed external funding and a small, founder-led operating profile; in 2024 it launched a Spanish beta of the thesaurus on Rimar.io and in 2026 marked its 30th anniversary with ongoing core product and game updates.

Name

OneLook

Legal name

OneLook (operated by Datamuse)

Website

https://onelook.com

Company type

Private

Founded year

1996

Operating status

Operating

Short description

OneLook is a 30-year-old English-language reference platform that aggregates 19+ million words from 1,000+ online dictionaries into a search engine, thesaurus, and reverse dictionary, serving writers, puzzle solvers, and language enthusiasts through its website, Google Docs add-on, iOS app, and Datamuse API.

Ownership category

akta.pro rank

Product category

Language Reference Software

NAICS

Web Search Portals and All Other Information Services (51929), Web Search Portals, Libraries, Archives, and Other Information Services (519)

SIC

Services-Computer Programming, Data Processing, Etc. (7370)

akta.pro primary industry

Meta-Search & Search Aggregators (BPAMAAAC)

akta.pro secondary industries

Search Engines (BPAMAAAB), Q&A and Knowledge Discovery Platforms (BPAMAAAF), Spelling, Vocabulary & Word Study Programs (EDAMAJAD)

Keywords

• Dictionary search engine
• Reverse dictionary
• Online thesaurus service
• Word games platform
• Language reference tools

GTM type

B2C

Offering type

Software

Cost components

Technology or R&D, Operations, Infrastructure, Personnel, Marketing or Sales

Revenue model

1. Advertising: Free ad-supported web service using third-party advertising companies. Users can disable banner advertisements via the Customize page. No personally identifying information is shared with advertisers.
2. iOS App Subscription: OneLook Thesaurus iPhone/iPad app available for a low subscription fee with a two-week free trial. Provides OneLook at fingertips with several app-only features while helping maintain the free service.

Pricing tiers

Go-to-market motion3 records

Distribution channels5 records

Marketing channels6 records

Core offering

OneLook operates a web-based dictionary search engine that indexes 19+ million words across more than 1,000 online dictionaries, enabling users to find definitions, related words, and quotes. Its flagship features include a reverse dictionary/thesaurus (2+ million words), advanced wildcard pattern matching, a subject index of 1.5 million words, a color thesaurus, and a suite of original word games (Cadgy, Threepeat, Compound Your Joy, Pandergram, Twisteroo, Banish Your Fears). The platform is exposed via a free ad-supported website, an iOS app, a Google Docs add-on, and the Datamuse API for developers.

Product overview

OneLook is a comprehensive English language reference platform consisting of multiple interconnected products. The core offering is the OneLook Dictionary Search engine (indexing over 16 million entries across 805 dictionaries) paired with the OneLook Thesaurus and Reverse Dictionary (covering over 2 million words). These are complemented by OneLook Word Games including Cadgy, Threepeat, Compound Your Joy, Pandergram, and Banish Your Fears, plus specialty features like the Subject Index (1.5 million words in concept clusters), Color Thesaurus, and History Tab (etymology and word popularity data). Supporting products include the Google Docs Add-On, iPhone/iPad app, Spruce quotations search, Saved Words feature, and the Wordplay newsletter. The platform is powered by the Datamuse API, with definitions sourced from Wiktionary, Wikipedia, and WordNet.

Differentiator

Problem solved

Functional benefit

Brands

• Cadgy: Daily word puzzle game where players find words in a letter grid
• Threepeat
• Compound Your Joy
• Pandergram
• Twisteroo
• Banish Your Fears
• Spruce
• OneLook Thesaurus

Products and services

• OneLook Dictionary Search A search engine for English words and phrases that indexes over 16 million entries across 805 dictionaries, used by writers, students, and general consumers to find definitions, related words, quotes, names, lyrics, and colors.
• OneLook Thesaurus / Reverse Dictionary A thesaurus and reverse dictionary covering 2+ million words and expressions, allowing users to enter a word, phrase, description, or pattern to find synonyms, related words, and concepts. Powers the 'find the right word' use case.
• Cadgy A daily word puzzle where players find words in a letter grid by picking one letter from each column, with Basic and Bonus word categories, shuffle, 3D view, and printable format.
• Threepeat A word game in which players find the common ground between words.
• Compound Your Joy A word pairing game where players find connections between word pairs by arranging them into familiar two-word concepts.
• Pandergram A word game designed to foster inclusion.
• Banish Your Fears A word game themed around fears and overcoming them.
• OneLook Thesaurus iOS App A native iPhone/iPad app providing OneLook Thesaurus functionality on mobile devices with app-only features, available with a two-week free trial and low subscription fee.
• OneLook Thesaurus Google Docs Add-On A free add-on for Google Docs that brings brainstorming capabilities directly into documents, with 9 function buttons for Synonyms, Triggers, Rhymes, Complete, Adjectives, Nouns, Quotes, Lyrics, and Poetry.
• Spruce A quotations search engine that finds relevant quotes from famous authors and celebrities based on meaning, sending search terms securely to the Datamuse API.

Segments4 records

Ideal customer profiles4 records

Technology focussed Yes

API detail

Has API

Yes

API docs

API detail

Core technology

AI maturity

App detail

Integration2 records

AI capability6 records

Feature9 records

Partnerships

One partnership is on record.

• DatamusecoreTechnology or IntegrationDatamuse is the parent company and owner of OneLook. The site uses the Datamuse API for processing queries. The API server maintains logs for 24 hours only and does not retain long-term usage data. Datamuse also owns RhymeZone, integrated into Merriam-Webster's site.

Scale indicators6 records

Recent moves6 records

Expansion highlights5 records

Direct peers

• Merriam-Webster: The flagship U.S. English dictionary website. Directly comparable as a destination for word definitions; additionally a distribution partner since Datamuse's RhymeZone is integrated into the Merriam-Webster site.
• Dictionary.com: Major consumer-facing online dictionary and thesaurus. Competes head-on with OneLook for definition and synonym lookup queries and operates a similar ad-supported free model.
• Thesaurus.com: Dedicated online thesaurus owned by Dictionary.com. Directly competes with OneLook's thesaurus and reverse dictionary for synonym and word-association queries.
• RhymeZone: Sister property also operated by Datamuse, the parent of OneLook. Closely comparable in product (rhyme/concept lookup) and shares the same Datamuse API infrastructure.
• PowerThesaurus.org: Community-driven online thesaurus. Targets the same synonym-seeking writers and students with a free, ad-supported web model directly comparable to OneLook.
• WordHippo: Multi-tool word reference site covering synonyms, antonyms, rhymes, translations, and word patterns. Closely overlaps OneLook's reverse dictionary and advanced pattern features.
• Spruce: Quotation search engine operated by Datamuse alongside OneLook. Uses the same API infrastructure and serves an overlapping writer/researcher audience seeking meaning-based retrieval.

Broad incumbents

• Cambridge Dictionary: Established academic dictionary publisher with a major free web dictionary. Competes for the same definition-lookup use case but operates as part of a broader publishing portfolio rather than as a niche word tool.
• Wiktionary: Free collaborative multilingual dictionary. Functionally a foundational data source OneLook relies on, and a competing free destination for word lookups.
• Google Dictionary: Dictionary lookups surfaced within Google Search and on dedicated pages. As a broad incumbent, it captures a share of definition queries that would otherwise go to standalone word sites.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights6 records

Customer concentration

Revenue estimate

Valuation estimate

Number of profiles

Subsidiaries1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about OneLook